Crystalline silicon solar cells have been widely known as a device for directly converting light energy into electric energy. The crystalline silicon solar cells are used as an independent power source, and a power source for use in a vehicle. The crystalline silicon solar cells are usually made of silicon single crystals or amorphous silicon. However, enormous amounts of energy is required to produce silicon single crystals or amorphous silicon, and in order to recover energy consumed for fabricating the solar cells, the solar cells needs to generate electric power continuously for almost as long as a ten-year period.
Meanwhile, in recent a few years, various forms of solar cells using organic molecules have been developed as a new form of a solar cell in which the technical possibility thereof has been rapidly improved. Existing organic solar cells developed until now are still at the beginning stages in energy conversion efficiency, service life, and the like. Presently, since the optical and electric stability of the organic molecules are not at a satisfactory level, the organic solar cell is one of the development fields of solar cells which have been widely studied even until now in order to improve the performances thereof.
Existing organic solar cells developed until now are very vulnerable to temperature, solar light, a high wavelength system, and the like and have many problems in energy conversion efficiency. Thus, those problems are obstacle factors to the development of solar cells using organic molecules, and particularly, because energy conversion efficiency of solar cells using organic materials is lower than that of the existing silicon solar cells, and the like and the solar cells have many limitations in use thereof, it is difficult to expand the use fields thereof.
As illustrated in the following FIG. 15, an organic solar cell in the related art comprises an indium tin oxide (ITO) electrode provided on a glass substrate, a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT/PSS) layer provided on the ITO electrode, an organic active layer provided on the PEDOT/PSS layer and the glass substrate, and an aluminum electrode provided on the organic active layer.